As hyperion is causing thousands (over 5K!) of errors, it makes the logs difficult to read. I’d suggest removing it to clean up the logs. Then maybe the other problem will become more obvious.
I also wonder just what this is coming from:
Dec 15 14:56:28 osmc sshd[3145]: Unable to negotiate with 115.238.245.2 port 38460: no matching key exchange method found. Their offer: diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1 [preauth]
Dec 15 15:00:02 osmc sshd[3178]: Unable to negotiate with 115.238.245.8 port 39675: no matching key exchange method found. Their offer: diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1 [preauth]
Dec 15 15:04:43 osmc sshd[3190]: Unable to negotiate with 115.238.245.2 port 35842: no matching key exchange method found. Their offer: diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1 [preauth]
Dec 15 15:05:27 osmc sshd[3192]: Unable to negotiate with 36.156.24.96 port 46784: no matching key exchange method found. Their offer: diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1 [preauth]
The log also has many of those. Do you have a VPN setup?
If do not have a VPN, then those lines in the log are troubling. Do you have port 22 open in your firewall? I hope that you have changed your osmc password!
I suspect that your system was compromised when you had port 22 open. A random sampling of IPs has them located in China. If port 22 is closed now then they should not be accessing your system, but they are reaching it.
I’d backup .kodi and re-install.
Did this lag start around the same time that you opened port 22
I just did a test. I have a 4K and Pi2 that had a shared MySQL database hosted on the 4K.
I updated the 4K to Kodi V18, but hadn’t kept the Pi2 updated.
The first update took 31 minutes. 100 new videos were added to the library. I have very slow satellite internet, and the Pi is connected via powerline.
I then ran the test again with 1 new video added and it took 2m54s to do the scan.